U.S. patent application number 14/713009 was filed with the patent office on 2015-12-17 for gas turbine engine lubrication system.
The applicant listed for this patent is United Technologies Corporation. Invention is credited to Gary D. Roberge.
Application Number | 20150361886 14/713009 |
Document ID | / |
Family ID | 53540572 |
Filed Date | 2015-12-17 |
United States Patent
Application |
20150361886 |
Kind Code |
A1 |
Roberge; Gary D. |
December 17, 2015 |
GAS TURBINE ENGINE LUBRICATION SYSTEM
Abstract
A lubrication system includes a lubrication tank, a gearbox
driven pump, an electrically driven pump located in parallel with
the gearbox driven pump, and a first control valve for selectively
connecting the electrically driven pump or the gearbox driven pump
with the lubrication tank.
Inventors: |
Roberge; Gary D.; (Tolland,
CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
United Technologies Corporation |
Hartford |
CT |
US |
|
|
Family ID: |
53540572 |
Appl. No.: |
14/713009 |
Filed: |
May 15, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62003577 |
May 28, 2014 |
|
|
|
Current U.S.
Class: |
417/53 ;
417/364 |
Current CPC
Class: |
F01M 1/12 20130101; F01M
2001/123 20130101; F01D 25/20 20130101; F16H 57/0439 20130101; F16N
2260/00 20130101; F02C 7/06 20130101 |
International
Class: |
F02C 7/06 20060101
F02C007/06 |
Claims
1. A lubrication system comprising: a lubrication tank; a gearbox
driven pump; an electrically driven pump located in parallel with
the gearbox driven pump; and a first control valve for selectively
connecting the electrically driven pump or the gearbox driven pump
with the lubrication tank.
2. The lubrication system as recited in claim 1, including a second
control valve located downstream of an output to the gearbox driven
pump and an output to the electrically driven pump.
3. The lubrication system as recited in claim 2, wherein the first
control valve and the second control valve are configured to
selectively move between a first position to allow lubricant only
through the gearbox driven pump and a second position to allow
lubricant only through the electrically driven pump.
4. The lubrication system as recited in claim 2, including a third
control valve located downstream of the second control valve for
selectively directing lubrication between at least one of a speed
change mechanism on a gas turbine engine and rotor support bearings
on the gas turbine engine.
5. The lubrication system as recited in claim 4, including a
lubrication cooler located downstream of the second control valve
and upstream of the third control valve.
6. The lubrication system as recited in claim 2, including a third
control valve located downstream of the second control configured
to selectively move between a first position for providing
lubricant to a speed change mechanism and bearing systems and a
second position for providing lubricant only to the speed change
mechanism.
7. The lubrication system as recited in claim 1, wherein the
electrically driven pump receives power from a vehicle power
distribution control.
8. The lubrication system as recited in claim 7, wherein the power
distribution control is in electrical communication with a first
gas turbine engine and a second gas turbine engine.
9. The lubrication system as recited in claim 1, including a
gearbox for driving the gearbox driven pump.
10. The lubrication system as recited in claim 9, including a tower
shaft mechanically connecting the gearbox with a high speed
spool.
11. A method of lubricating a speed change mechanism on a gas
turbine engine comprising: selecting a first pump to supply
lubricant to the speed change mechanism and bearing systems in
response to a first vehicle condition; selecting a second pump to
supply lubricant to the speed change mechanism in response to a
second vehicle condition, wherein the first pump is located fluidly
in parallel with the second pump.
12. The method as recited in claim 11, including driving the first
pump with a gearbox.
13. The method as recited in claim 12, wherein the first vehicle
condition is operation of the gas turbine engine.
14. The method as recited in claim 13, wherein the second vehicle
condition includes at least one of wind milling or a stall of the
gas turbine engine.
15. The method as recited in claim 12, including driving the second
pump with an electric motor.
16. The method as recited in claim 15, wherein the second pump
receives power from a power distribution control on a vehicle.
17. The method as recited in claim 16, wherein the power
distribution control receives power from a second gas turbine
engine.
18. The method as recited in claim 11, including supplying
lubrication to rotor bearings on a gas turbine engine with the
first pump.
19. The method as recited in claim 11, including a first valve and
a second valve for selectively moving between a first position
allowing fluid to flow through the first pump and a second position
allowing fluid to flow through the second pump.
20. The method recited in claim 11, including a third valve for
selectively directing fluid to at least one of the speed change
mechanism or the bearing systems on the gas turbine engine.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application No. 62/003,577, which was filed on May 28, 2014 and is
incorporated herein by reference.
BACKGROUND
[0002] This disclosure relates to a lubrication system for
providing lubricant to a gas turbine engine, and more particularly,
to a bearing system and a geared architecture on the gas turbine
engine.
[0003] Gas turbine engines typically include a fan section, a
compressor section, a combustor section, and a turbine section. Air
entering the compressor section is compressed and delivered into
the combustion section where it is mixed with fuel and ignited to
generate a high-speed exhaust gas flow. The high-speed exhaust gas
flow expands through the turbine section to drive the compressor
and the fan section.
[0004] The gas turbine engine includes various components that
require lubrication. A main lubrication system generally provides
lubrication to these components. A pump for the main lubrication
system is generally powered by a gearbox in communication with a
spool on the gas turbine engine through a tower shaft.
SUMMARY
[0005] In one exemplary embodiment, a lubrication system includes a
lubrication tank, a gearbox driven pump, an electrically driven
pump located in parallel with the gearbox driven pump, and a first
control valve for selectively connecting the electrically driven
pump or the gearbox driven pump with the lubrication tank.
[0006] In a further embodiment of any of the above, a second
control valve is located downstream of an output to the gearbox
driven pump and an output to the electrically driven pump.
[0007] In a further embodiment of any of the above, the first
control valve and the second control valve are configured to
selectively move between a first position to allow lubricant only
through the gearbox driven pump and a second position to allow
lubricant only through the electrically driven pump.
[0008] In a further embodiment of any of the above, a third control
valve is located downstream of the second control valve for
selectively directing lubrication between at least one of a speed
change mechanism on a gas turbine engine and rotor support bearings
on the gas turbine engine.
[0009] In a further embodiment of any of the above, a lubrication
cooler is located downstream of the second control valve and
upstream of the third control valve.
[0010] In a further embodiment of any of the above, a third control
valve is located downstream of the second control configured to
selectively move between a first position for providing lubricant
to a speed change mechanism and bearing systems and a second
position for providing lubricant only to the speed change
mechanism.
[0011] In a further embodiment of any of the above, the
electrically driven pump receives power from a vehicle power
distribution control.
[0012] In a further embodiment of any of the above, the power
distribution control is in electrical communication with a first
gas turbine engine and a second gas turbine engine.
[0013] In a further embodiment of any of the above, there is a
gearbox for driving the gearbox driven pump.
[0014] In a further embodiment of any of the above, a tower shaft
mechanically connects the gearbox with a high speed spool.
[0015] In another exemplary embodiment, a method of lubricating a
speed change mechanism on a gas turbine engine includes selecting a
first pump to supply lubricant to the speed change mechanism and
bearing systems in response to a first vehicle condition and
selecting a second pump to supply lubricant to the speed change
mechanism in response to a second vehicle condition. The first pump
is located fluidly in parallel with the second pump.
[0016] In a further embodiment of the above, the method includes
driving the first pump with a gearbox.
[0017] In a further embodiment of any of the above, the first
vehicle condition is operation of the gas turbine engine.
[0018] In a further embodiment of any of the above, the second
vehicle condition includes at least one of wind milling or a stall
of the gas turbine engine.
[0019] In a further embodiment of any of the above, the method
includes driving the second pump with an electric motor.
[0020] In a further embodiment of any of the above, the second pump
receives power from a power distribution control on a vehicle.
[0021] In a further embodiment of any of the above, the power
distribution control receives power from a second gas turbine
engine.
[0022] In a further embodiment of any of the above, the method
includes supplying lubrication to rotor bearings on a gas turbine
engine with the first pump.
[0023] In a further embodiment of any of the above, the method
includes a first valve and a second valve for selectively moving
between a first position and to allow fluid to flow through the
first pump and a second position to allow fluid to flow through the
second pump.
[0024] In a further embodiment of any of the above, the method
includes a third valve for selectively directing fluid to at least
one of the speed change mechanism or the bearing systems on the gas
turbine engine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 shows a schematic view of an example gas turbine
engine.
[0026] FIG. 2 shows an example lubrication system.
[0027] FIG. 3 shows an example vehicle.
DETAILED DESCRIPTION
[0028] FIG. 1 schematically illustrates a gas turbine engine 20.
The gas turbine engine 20 is disclosed herein as a two-spool
turbofan that generally incorporates a fan section 22, a compressor
section 24, a combustor section 26 and a turbine section 28.
Alternative engines might include an augmentor section (not shown)
among other systems or features. The fan section 22 drives air
along a bypass flow path B in a bypass duct defined within a
nacelle 15, while the compressor section 24 drives air along a core
flow path C for compression and communication into the combustor
section 26 then expansion through the turbine section 28. Although
depicted as a two-spool turbofan gas turbine engine in the
disclosed non-limiting embodiment, it should be understood that the
concepts described herein are not limited to use with two-spool
turbofans as the teachings may be applied to other types of turbine
engines including three-spool architectures.
[0029] The exemplary engine 20 generally includes a low speed spool
30 and a high speed spool 32 mounted for rotation about an engine
central longitudinal axis A relative to an engine static structure
36 via several bearing systems 38. It should be understood that
various bearing systems 38 at various locations may alternatively
or additionally be provided, and the location of bearing systems 38
may be varied as appropriate to the application.
[0030] The low speed spool 30 generally includes an inner shaft 40
that interconnects a fan 42, a first (or low) pressure compressor
44 and a first (or low) pressure turbine 46. The inner shaft 40 is
connected to the fan 42 through a speed change mechanism, which in
exemplary gas turbine engine 20 is illustrated as a geared
architecture 48 to drive the fan 42 at a lower speed than the low
speed spool 30. The high speed spool 32 includes an outer shaft 50
that interconnects a second (or high) pressure compressor 52 and a
second (or high) pressure turbine 54. A combustor 56 is arranged in
exemplary gas turbine 20 between the high pressure compressor 52
and the high pressure turbine 54. A mid-turbine frame 57 of the
engine static structure 36 is arranged generally between the high
pressure turbine 54 and the low pressure turbine 46. The
mid-turbine frame 57 further supports bearing systems 38 in the
turbine section 28. The inner shaft 40 and the outer shaft 50 are
concentric and rotate via bearing systems 38 about the engine
central longitudinal axis A which is collinear with their
longitudinal axes.
[0031] The core airflow is compressed by the low pressure
compressor 44 then the high pressure compressor 52, mixed and
burned with fuel in the combustor 56, then expanded over the high
pressure turbine 54 and low pressure turbine 46. The mid-turbine
frame 57 includes airfoils 59 which are in the core airflow path C.
The turbines 46, 54 rotationally drive the respective low speed
spool 30 and high speed spool 32 in response to the expansion. It
will be appreciated that each of the positions of the fan section
22, compressor section 24, combustor section 26, turbine section
28, and fan drive gear system 48 may be varied. For example, gear
system 48 may be located aft of combustor section 26 or even aft of
turbine section 28, and fan section 22 may be positioned forward or
aft of the location of gear system 48.
[0032] The engine 20 in one example is a high-bypass geared
aircraft engine. In a further example, the engine 20 bypass ratio
is greater than about six (6), with an example embodiment being
greater than about ten (10), the geared architecture 48 is an
epicyclic gear train, such as a planetary gear system or other gear
system, with a gear reduction ratio of greater than about 2.3 and
the low pressure turbine 46 has a pressure ratio that is greater
than about five. In one disclosed embodiment, the engine 20 bypass
ratio is greater than about ten (10:1), the fan diameter is
significantly larger than that of the low pressure compressor 44,
and the low pressure turbine 46 has a pressure ratio that is
greater than about five 5:1. Low pressure turbine 46 pressure ratio
is pressure measured prior to inlet of low pressure turbine 46 as
related to the pressure at the outlet of the low pressure turbine
46 prior to an exhaust nozzle. The geared architecture 48 may be an
epicycle gear train, such as a planetary gear system or other gear
system, with a gear reduction ratio of greater than about 2.3:1. It
should be understood, however, that the above parameters are only
exemplary of one embodiment of a geared architecture engine and
that the present invention is applicable to other gas turbine
engines including direct drive turbofans.
[0033] A significant amount of thrust is provided by the bypass
flow B due to the high bypass ratio. The fan section 22 of the
engine 20 is designed for a particular flight condition--typically
cruise at about 0.8 Mach and about 35,000 feet. The flight
condition of 0.8 Mach and 35,000 ft (10,668 meters), with the
engine at its best fuel consumption--also known as "bucket cruise
Thrust Specific Fuel Consumption ('TSFC')"--is the industry
standard parameter of lbm of fuel being burned divided by lbf of
thrust the engine produces at that minimum point. "Low fan pressure
ratio" is the pressure ratio across the fan blade alone, without a
Fan Exit Guide Vane ("FEGV") system. The low fan pressure ratio as
disclosed herein according to one non-limiting embodiment is less
than about 1.45. "Low corrected fan tip speed" is the actual fan
tip speed in ft/sec divided by an industry standard temperature
correction of [(Tram .degree.R)/(518.7.degree. R)]0.5. The "Low
corrected fan tip speed" as disclosed herein according to one
non-limiting embodiment is less than about 1150 ft/second (350.5
meters/second).
[0034] FIG. 2 shows a schematic view of a lubrication system 60 for
the gas turbine engine 20. The lubrication system 60 provides
lubricant, such as oil, to the geared architecture 48 and the
bearing systems 38.
[0035] Oil collected from a scavenge system 61 is directed to an
oil tank 62. A first control valve 68 directs the oil to a gearbox
driven pump 64 when the first control valve is in a first position
and to an electrically driven pump 66 when the first control valve
68 is in a second position.
[0036] The gearbox driven pump 64 is driven by a gearbox 70. The
gearbox 70 receives rotational input from the high speed spool 32
through a tower shaft 72. During operation of the gas turbine
engine 20, the rotation of the high speed spool 32 provides
sufficient power for the gearbox driven pump 64 to pump oil to the
geared architecture 48 and the bearing systems 38.
[0037] The electrically driven pump 66 is driven by an electric
motor that receives power from a power distribution control 74. In
one example, the power distribution control 74 receives electrical
power from generators powered by separate gas turbine engines 20 on
an aircraft 10 as shown in FIG. 3.
[0038] A second control valve 76 is located downstream of outputs
to both the electrically driven pump 66 and the gearbox driven pump
64 such that the pumps 64 and 66 are located fluidly in parallel.
The second control valve 76 moves between a first position allowing
oil from the gearbox driven pump 64 to reach the gas turbine engine
20 and a second position allowing oil from the electrically driven
pump 66 to reach the gas turbine engine 20.
[0039] A third control valve 78 is located downstream of the second
control valve 76. The second control valve 78 selectively directs
oil to either the bearing systems 38 and the geared architecture 48
when in a first position or only the geared architecture 48 when in
a second position. A supply manifold supplies oil to the bearing
systems 38 through multiple conduits 81 extending between the
supply manifold 80 and the bearing systems 38.
[0040] An oil cooler 82 is located downstream of the second control
valve 76 and upstream of the third control valve 78 for cooling the
oil before the oil enters the geared architecture 48 or the bearing
systems 38 through the supply manifold 80.
[0041] The lubrication system 60 is operated by selecting either
the gearbox driven pump 64 or the electrically driven pump 66 to
provide lubricant to at least one of the geared architecture 48 and
the bearing systems 38. The gearbox driven pump 64 provides
lubricant to both the geared architecture 48 and the bearing
systems 38 during normal operation of the gas turbine engine 20 by
receiving power through the gearbox 70. To utilize the gearbox
driven pump 64, the first, second, and third control valves are
moved to the first position and oil is able to flow to the geared
architecture 48 and the bearing systems 38.
[0042] The electrically driven pump 66 is used when the gas turbine
engine 20 is wind milling after engine shutdown to provide
continued flow of lubricant to at least the geared architecture 48
under conditions where the gearbox driven pump 64 to longer
receives sufficient power from the gearbox 70 to pump oil to the
geared architecture 48 and the bearing systems 38. The electrically
driven pump 66 receives power from a power distribution control 74
on the aircraft 10. The power distribution control 74 receives
power from each of the gas turbine engines 20 on the aircraft as
well as an auxiliary power supply unit on the aircraft 10 if
present. To utilize the electrically driven pump 66, the first,
second, and third valve controls are moved to the second position
and oil is able to flow to only the geared architecture 48.
[0043] In an alternative embodiment, the electrically driven pump
66 can also be used when an anomaly is detected within the
lubrication system 60 in the gas turbine engine 20. In this
embodiment, the electrically driven pump 66 receives power from
power distribution control 74 to supply oil to both the geared
architecture 48 and the bearing systems 38. In order to supply oil
to both the geared architecture 48 and the bearing systems 38, the
first control valve 68 and the second control valve 76 moves into
the second position and the third control valve 78 moves into the
first position.
[0044] The preceding description is exemplary rather than limiting
in nature. Variations and modifications to the disclosed examples
may become apparent to those skilled in the art that do not
necessarily depart from the essence of this disclosure. The scope
of legal protection given to this disclosure can only be determined
by studying the following claims.
* * * * *